The Schneider Electric TA16D4S1254TPE is an automatic transfer switch from the TransferPacT range, rated 125 A at 400 V AC 50/60 Hz with 4 poles. It is a PC-class switch per IEC 60947-6-1, meaning it is designed for full-rated current switching without overload protection built in — the upstream breaker handles fault clearing. The AC-33B utilization category covers motor, resistive, and mixed loads including tungsten lamps, making it suitable for general building services and industrial changeover applications where the load is a mix of motors and lighting. Control is via a rotary knob selector switch with automatic and manual operating modes. Signal contacts are configurable as 1 NO + 2 NC or 1 NC + 2 NO or 2 NO, giving flexibility for remote status monitoring.
The switch is rated for uninterrupted duty, meaning it can carry 125 A continuously without cycling. The rated short-time withstand current (Icw) of 10 kA for 0.1 s defines how much fault current the switch can survive while the upstream breaker clears; the short-circuit making capacity (Icm) of 154 kA with an upstream breaker at 400 V AC tells you the switch can close onto a fault of that magnitude without welding contacts. Without the upstream breaker, the switch alone makes 20 kA. Rated insulation voltage (Ui) is 800 V for the switch and 500 V for the controller, with impulse withstand (Uimp) of 8 kV and 6 kV respectively — this covers the transient overvoltage environment in a 400 V distribution panel.
The connection pitch is 30 mm, and both upside and downside connections are screwed terminals — expect to land cable lugs or busbars. Front face is IP40 in auto mode (finger-safe against tools >1 mm), inside the enclosure is IP20 in manual mode (finger-safe). Dimensions are 351 mm wide by 164 mm high by 95 mm deep, so plan for a panel cutout or enclosure depth that clears the rear of the switch with wiring space.